Improvement in dental chairs



.E. T. STARR.

DENTAL-CHAIR.

Patented De c. 21, 1875.

N. PETERS, PHDTD-LITHOGRAPHER. WASHINGTON. D C.

UNITED STATEs PATENT OFFICE.

ELI T..STARR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO SAMUEL S.WHITE, OF SAME PLACE.

IMPROVEMENT IN DENTAL CHAIRS.

Specification forming part of Letters Patent No. 171,443, dated December21, 1875; application filed November 5, 1875.

To all whom it may concern:

Be it known that I, ELI T. STARR, of the city of Philadelphia and Stateof Pennsylvania, have invented a certain new and useful Improvement inDentists Chairs, of which the following is a specification My inventionrelates to dentists chairs of that class provided with means for raisingand lowering the seat.

The subject-matter claimed will hereinafter specifically be designated.

In the accompanying drawings, Figure 1 represents a view of so much ofmy improved elevating apparatus as is necessary to illustrate thesubject-matter herein claimed Fig.

2, a horizontal section therethrough on the line of the fixed nut, andFig. 3 a vertical section through the apparatus.

The base A of the chair may be constructed in any of the usualwell-known ways, and is provided at its upper end with a collar, a, inwhich a tubular sleeve, B, fits snugly and moves freely endwise, but isprevented from turning by lugs 12 of a nut, C, fixed in the collar a,which lugs pass through vertical slots b in the walls of the tubularsleeve. A screwspindle, D, inclosed within the sleeve, passes Ithrough'the nut U, and has mounted upon its upperend a bevel-pinion,d,driven byacorrespondin g pinion, a, mounted on a shaft, E, supportedupon the frame of the chair and driven in any of the usual well-knownways. The turning of this screw raises or lowers both it and itsenveloping sleeve, and, of course, the body of the chair also, while theends of the slots in the sleeve act as stops to limit the range ofadjustment of the chair.

My invention enables me to protect the screw and secure a strong,simple, and convenient method of adjustment, While enabling me todispense with a fixed screw-sleeve, such as has heretofore in oneinstance been employed.

I do not broadly claim the combination of a movable sleeve and a spindleinclosed therein but I claim as of my own invention- The chair-elevatingapparatus hereinbefore

